Abstract: An operation-supporting apparatus includes: an operation request input unit that inputs information relating to operation request items of plant equipment; an operating conditions setting unit that converts operation request input information to operating parameters; an operation history creation unit that creates an operation history by chronologically processing the operating parameters; a breakdown statistics database that stores an event tree of the plant equipment; an event simulator that calculates the degree of unreliability corresponding to the operating parameters, the operation request information, and the operation history information, and in compliance with the event tree; a risk-cost calculation unit that calculates risk-cost by determining the aggregate product of the degrees of unreliability and restoration costs; an operating method determination unit that determines whether operating conditions are suitable by comparing the risk-cost with profit gained by continuing operation; and an operatin

Abstract: It is an object of this invention to provide an apparatus that selects and specifies an optimal operating method for plant equipment while estimating risk-cost that relates to damage, performance deterioration, and functional stoppage, of the plant equipment, and comparing the risk-cost with profit gained from operation.

Abstract: The present invention provides a method of inspecting a target component part (e.g., valve casing) of an apparatus (e.g., steam control valve) included in a steam turbine system. When a time period in a range of 24 to 100 hours passes from the shutting-down of the turbine system, or before a temperature of an atmosphere surrounding the component part is lowered to 100° C., the width of the opening of the crack formed in the component part or a clearance relating to the component part is measured without disassembling the target component part and an enclosing member (e.g., valve casing) from the apparatus. As the measurement is performed when a thermal stress is induced in the component parts or when the temperature distribution is wide, the risk level of the crack or the clearance is determined accurately.

Abstract: Data on inspection, diagnosis, repair and operation histories are entered in a plant-maintenance apparatus for equipment that constitute a plant to be maintained. Failure-event tree breakdown is performed on failures to be expected for the equipment. Unreliability is predicted of at least one starting item in the failure-event tree breakdown. Unreliability of each item in the failure-event tree is calculated based on a failure unreliability function. Unreliability and a cost of recovery from each failure event in the failure-event tree are multiplied and results of the multiplication are accumulated in accordance with the tree breakdown to obtain a recovery cost. Preventive maintenance expenses are calculated for preventing failure events. Maintenance timing and technique are decided through comparison between the recovery cost and the preventive maintenance expenses.

Abstract: An apparatus for maintaining plant equipment incorporates an input unit to receive information on targets and ranges of plant equipment to be maintained and a failure-event tree breakdown unit to perform tree-breakdown on failures to be expected from events to be inspected. A failure-unreliability function calculation unit calculates unreliability of each item in failure-event tree breakdown and a failure-derived monetary loss calculation unit multiplies each unreliability and a cost of recovery from each event in accordance with the failure-event tree breakdown. A preventive maintenance expense calculation unit calculates preventive maintenance expenses for preventing failure events and a maintenance decision-making unit decides maintenance timing and technique through comparison between the recovery cost and the preventive maintenance expense.

Abstract: The present invention provides a method of inspecting a target component part (e.g., valve casing) of an apparatus (e.g., steam control valve) included in a steam turbine system. When a time period in a range of 24 to 100 hours passes from the shutting-down of the turbine system, or before a temperature of an atmosphere surrounding the component part is lowered to 100° C., the width of the opening of the crack formed in the component part or a clearance relating to the component part is measured without disassembling the target component part and an enclosing member (e.g., valve casing) from the apparatus. As the measurement is performed when a thermal stress is induced in the component parts or when the temperature distribution is wide, the risk level of the crack or the clearance is determined accurately.

Abstract: Entered in a plant-maintenance apparatus are data on inspection, diagnosis, repair and operation histories for equipment that constitute a plant to be maintained. Failure-event tree breakdown is performed on failures to be expected for the equipment. Predicted is unreliability of at least one starting item in the failure-event tree breakdown. Unreliability of each item in the failure-event tree is calculated based on failure unreliability function. Unreliability and a cost of recovery from each failure event in the failure-event tree are multiplied and results of the multiplication are accumulated in accordance with the tree breakdown, thus obtaining a recovery cost. Preventive maintenance expenses are calculated for preventing failure events. Maintenance timing and technique are decided through comparison between the recovery cost and the preventive maintenance expenses.

Abstract: An apparatus for maintaining plant equipment incorporates: an input unit to receive information on targets and ranges of plant equipment to be maintained, that constitute a plant, inspection information and operation-history information; a failure-event tree breakdown unit to perform tree-breakdown on failures to be expected from events to be inspected; a failure-unreliability function calculation unit to calculate unreliability of each item in the failure-event tree breakdown; a failure-derived monetary loss calculation unit to multiply each unreliability and a cost of recovery from each event to be inspected and accumulate results of multiplication in accordance with the failure-event tree breakdown, thus obtaining a recovery cost; a preventive maintenance expense calculation unit to calculate preventive maintenance expenses for preventing failure events; and a maintenance decision-making unit to decide maintenance timing and technique through comparison between the recovery cost and the preventive maintena

Abstract: In an axial-flow turbine, at least one of front and rear side contact surfaces of shrouds (3a or 3b) of blades (1a or 1b) with respect to the turbine rotational direction is formed at certain angle with respect to a radial line connecting the rotor center and the contact surface. The shroud (3a) of the blade (1a) of a first kind is formed in a trapezoidal shape converging radially outward in cross section taken in a plane perpendicular to the turbine axial direction, and the shroud (3b) of the blade (1b) of a second kind is formed in an inverted trapezoidal shape converging radially inward in the cross section. Further, half of an angle (2.alpha.) between the front and rear side contact surfaces of the shrouds (3a or 3b) is made smaller than a static frictional angle of the contact surface.

Abstract: A magnetic disk includes two kinds of texture lines formed on a substrate rendered to texturing, one kind being formed over the entire substrate and parallel with a circumference of the substrate and the other kind being formed such that a line tangent to the other texture intersects a line tangent to the one texture at an angle of 3 to 9 degrees. The other texture lines are yielded by processing the substrate with a polishing tape rocking the substrate radially thereof, and satisfying the floating characteristic of a magnetic head as being floated in a low degree, the contact-start-stop characteristic, and the attraction characteristic.